Spring-end connection



June 5, 1934. H. COLOMB SPRING END CONNECTION Filed Sept. 9, 1931Patented June 5, 1934 UNITE STATES PATENT? OFFICE Application September9, 1931, Serial No. 561,918

In Switzerland September 17, 1930 Claims. (01. 58-83) This inventionrelates to spring-end connections in watch or clock barrels and has asits object the provision of means to prevent overwinding and rupture ofthe main driving spring 5 of timepieces.

It is already known to insert a friction ring in the spring barrel, thering being designed so as to exert a pressure of given amount on theinner cylindrical wall of the barrel and to have the spring endconnected to this ring, so that after the spring has been tensioned tothe desired limit the power of the spring exceeds the friction betweenthe ring and the barrel and further winding of the spring results inmoving the ring relative to the barrel.

According to the present invention use is also made of a friction ring,but this friction ring has two spaced ends so as not to extend over theentire circumference of the barrel, the

' spring being provided with an end member freely disposed in the spaceleft between the two ends of the ring.

In the accompanying drawing Figure 1 is a plan view of a spring barrelshowing a spring end connection according to the invention, the springbeing deenergized.

Figure 2 is a similar View of a spring barrel showing the spring inwound up position.

Figures 3, 4 and 5 are fragmentary cross sections through threemodifications of a spring end connection according to the invention.

Figures 6 and 7 show in elevation and plan, respectively, the frictionring end of the modification according to Fig. 5.

3 In Figures 1 and 2, 1 indicates the spring barrel the cover of whichhas been removed. The main driving spring 3 is connected in well knownmanner to the winding shaft 2. The resilient M. friction ring 4 isapplied with pressure against the cylindrical inner wall of thebarrel 1. This ring 4 extends over less than the entire circumference ofthe barrel leaving a free space 10 between its two ends to expose aportion of the l, inner surface of the barrel. The outer end of thedriving spring 3 has a blade-shaped end member 5 riveted or otherwiseattached to it, this end member extending at the exterior side of thespring rearwardly relative to the spring and being circularly curved andof such length that it can be passed into the space 10 between the twoends of the friction ring to bear with its entire length against theexposed portion of the inner surface of the barrel. When the ...spring 3is wound up, the free end 6 of the end member 5 abuts against the end ofthe friction ring 4, which ring is so dimensioned that after the desiredamount of tension of the spring is reached, it starts to slidecircumferentially relative to the barrel 1.

In spring barrels heretofore in use in which a friction ring has beenemployed to avoid overwinding of the driving spring, the end of thespring has been riveted or otherwise permanently connected to thefriction ring. The value of friction between the ring and the barrel insuch constructions is exactly calculated in order to obtain the desiredmaximum tension of the main spring, and this value of friction dependsnaturally from the dimensions of the portions of the ring which are incontact with the barrel.

In such constructions in which the ring is per manently connected to themain spring, this connection has to be made before the two parts areinserted into the barrel, since the spring has to be inserted whilebeing loose and then there would be no room in the barrel to make theconnection with the ring. The insertion of a spring into the barrel isknown to be a rather complicated operation and when the friction ringand the spring have to be inserted together, it is possible that thering can be deformed and after insertion does not act on the barrel withthe predetermined force, so that the value of friction is changed andtherefore the end tension of the spring changes also.

A further drawback in attaching the friction ring to the spring consistsin that the spring, when fully tensioned, pulls the end of the frictionring where it is attached, towards the interior of the barrel, so that aportion of the ring is not more in contact with the barrel and the valueof friction is again changed.

These drawbacks are avoided with the spring end connection according tothe invention. Since there exists no connection between the spring andthe friction ring, this ring can be inserted alone in the barrel withthe necessary care and afterwards the spring will be inserted of whichthe end member enters the space between the two friction ring ends assoon as the spring is wound up.

Figures 3 to 7 concern modifications of the spring end connectiondescribed with reference to Figs. 1 and 2. In Fig. 3 the friction ring 4is inserted into a circular groove 9 formed in the barrel wall.

In Figs. 4 to 7, the free end 4a (Fig. 4) 4b (Figs. 5 to 7), of thefriction ring or of the spring end member, has a specially shapedtransverse section in order to enlargen the bearing surface and tobetter prevent the spring end member from sliding off the end of thefriction ring. In Figs. 5, 6 and 7 the free end 4b of the friction ringor of the spring end member, or of both the ring and the end member, isprovided with a central bulged portion 7.

I claim:

1. In a spring driving mechanism, a spring barrel, a winding shaft, anopen friction ring bearing with the whole of its surface against theinner surface of the spring barrel and being shorter than the innerperiphery of the barrel so that a portion of the inner periphery of thebarrel is exposed between the two ends of the friction ring, a drivingspring having its inner end connected to the winding shaft and havingits outer end provided with a circularly curved end member freelypassing into the space between the two ends of the friction ring to bearwith its entire length against the exposed portion of the periphery ofthe barrel, the free end of, said end member bearing against one end ofthe friction ring upon tensioning of the driving spring.

2. In a spring driving mechanism, a circular spring barrel, a windingshaft, an open friction ring bearing with its entire length against theinner circular surface of the barrel and being of shorter length thanthe inner periphery of the barrel so that a portion of the inner surfaceof the barrel is exposed between the spaced ring ends, a driving springhaving its inner end connected to the driving shaft, and a circularlycurved blade-shaped member secured to the outer end of the drivingspring and being of such length as to freely pass into the space betweenthe two ring ends to bear against the exposed portion of the innersurface of the barrel, whereby one end of said blade-shaped member abutsagainst one end of the friction ring upon winding of the driving spring.

3. In a spring driving mechanism, a spring barrel, a winding shaft, anopen friction ring bearing with its entire length against the innersurface of the barrel and being of shorter length than the innerperiphery of the barrel so that a portion of the inner surface of thebarrel is exposed between the two ends of the ring, a driving springhaving its inner end connected to the winding shaft, and a circularlycurved blade-shaped end member secured to the outer end of the drivingspring and extending at the exterior side of the spring rearwardlyrelative to the spring, said end member passing into the space leftbetween the two ends of the friction ring to bear with its entire lengthagainst the exposed portion of the inner surface of the spring barrel,whereby upon winding of the spring, the free end of said end memberabuts against one end of the friction ring to impart tangential pressureon the friction ring.

4. A spring driving mechanism such as defined in claim 3 and wherein theend of the friction ring abutting against said blade-shaped end memberupon winding of the driving spring is bulged to enlargen the bearingsurface between end member and friction ring.

5. A spring driving mechanism as claimed in claim 3 and wherein the freeend of said bladeshaped end member abutting against one end of thefriction ring upon winding of the driving spring is bulged to enlargenthe bearing surface between end member and friction ring.

HENRI COLOIKB.

